Watched this one too, and I have to think that there were WAY too many missed opportunities and moments where he would have acted different if he was walling. He did, generally, go to high volume areas and aim for head level. The triple kill can be attributed to luck, came around, saw the guy, plugged the head, got shot in the back, turned and killed, then waited for anybody that would see him on the map, got lucky and baited the guy who went looking for him. No foul here.